/**
 * ***************************************************************************** Copyright (c) 2000,
 * 2006 IBM Corporation and others. All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0 which accompanies this
 * distribution, and is available at http://www.eclipse.org/legal/epl-v10.html
 *
 * <p>Contributors: IBM Corporation - initial API and implementation
 * *****************************************************************************
 */
package org.eclipse.che.plugin.java.server.jdt.testplugin;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jdt.internal.ui.JavaPlugin;
import org.eclipse.ui.wizards.datatransfer.IImportStructureProvider;

/**
 * This class provides information regarding the context structure and content of specified zip file
 * entry objects.
 */
public class ZipFileStructureProvider implements IImportStructureProvider {
  private ZipFile zipFile;

  private ZipEntry root = new ZipEntry("/"); // $NON-NLS-1$

  private Map children;

  private Map directoryEntryCache = new HashMap();

  /**
   * Creates a <code>ZipFileStructureProvider</code>, which will operate on the passed zip file.
   *
   * @param sourceFile the zip file used to create this structure provider
   */
  public ZipFileStructureProvider(ZipFile sourceFile) {
    super();
    zipFile = sourceFile;
  }

  /** Adds the specified child to the internal collection of the parent's children. */
  protected void addToChildren(ZipEntry parent, ZipEntry child) {
    List childList = (List) children.get(parent);
    if (childList == null) {
      childList = new ArrayList();
      children.put(parent, childList);
    }

    childList.add(child);
  }

  /**
   * Creates a new container zip entry with the specified name, iff it has not already been created.
   */
  protected void createContainer(IPath pathname) {
    if (directoryEntryCache.containsKey(pathname)) {
      return;
    }

    ZipEntry parent;
    if (pathname.segmentCount() == 1) {
      parent = root;
    } else {
      parent = (ZipEntry) directoryEntryCache.get(pathname.removeLastSegments(1));
    }

    ZipEntry newEntry = new ZipEntry(pathname.toString());
    directoryEntryCache.put(pathname, newEntry);
    addToChildren(parent, newEntry);
  }

  /** Creates a new file zip entry with the specified name. */
  protected void createFile(ZipEntry entry) {
    IPath pathname = new Path(entry.getName());
    ZipEntry parent;
    if (pathname.segmentCount() == 1) {
      parent = root;
    } else {
      parent = (ZipEntry) directoryEntryCache.get(pathname.removeLastSegments(1));
    }

    addToChildren(parent, entry);
  }

  /* (non-Javadoc)
   * Method declared on IImportStructureProvider
   */
  public List getChildren(Object element) {
    if (children == null) {
      initialize();
    }

    return ((List) children.get(element));
  }

  /* (non-Javadoc)
   * Method declared on IImportStructureProvider
   */
  public InputStream getContents(Object element) {
    try {
      return zipFile.getInputStream((ZipEntry) element);
    } catch (IOException e) {
      JavaPlugin.log(e);
      return null;
    }
  }

  /* (non-Javadoc)
   * Method declared on IImportStructureProvider
   */
  public String getFullPath(Object element) {
    return ((ZipEntry) element).getName();
  }

  /* (non-Javadoc)
   * Method declared on IImportStructureProvider
   */
  public String getLabel(Object element) {
    if (element.equals(root)) {
      return ((ZipEntry) element).getName();
    }

    return new Path(((ZipEntry) element).getName()).lastSegment();
  }

  /**
   * Returns the entry that this importer uses as the root sentinel.
   *
   * @return java.util.zip.ZipEntry
   */
  public ZipEntry getRoot() {
    return root;
  }

  /**
   * Returns the zip file that this provider provides structure for.
   *
   * @return the zip file this provider provides structure for
   */
  public ZipFile getZipFile() {
    return zipFile;
  }

  /**
   * Initializes this object's children table based on the contents of the specified source file.
   */
  protected void initialize() {
    children = new HashMap(1000);

    Enumeration entries = zipFile.entries();
    while (entries.hasMoreElements()) {
      ZipEntry entry = (ZipEntry) entries.nextElement();
      if (!entry.isDirectory()) {
        IPath path = new Path(entry.getName()).addTrailingSeparator();
        int pathSegmentCount = path.segmentCount();

        for (int i = 1; i < pathSegmentCount; i++) {
          createContainer(path.uptoSegment(i));
        }
        createFile(entry);
      }
    }
  }

  /* (non-Javadoc)
   * Method declared on IImportStructureProvider
   */
  public boolean isFolder(Object element) {
    return ((ZipEntry) element).isDirectory();
  }
}
